Sunday, January 17, 2010

No, not part 3 of the weight loss series, don't worry. Rather, it's a response to your many emails and comments to Part 2 of the series that looked at calories in, calories out, and the principle of weight loss. As usual, there are too many good comments to do justice to with an answer, so I'll thank you once again and move ahead to a general response. Also, I wanted to write briefly on what is still coming, because there are some things I want to cover in future posts which come up over and over in the early posts as well.

One common theme in your responses has been 'complexity', and this is something that has weighed (pardon the pun!) on me as I've written these last two posts. As I stressed yesterday, weight loss is not simple (obesity wouldn't be the fastest growing cause of death if it were), but at the same time, it must be simplified, because so many layers of misinformation have been added over the years (and the 87,000 books) that many have become entrenched as 'best practice' that it actually serves to go back before going forward!

The simplicity is the calories argument, the principle that energy out must exceed energy in for weight loss to occur. However, I wouldn't recommend taking the approach of counting calories to try to balance the equation, because of inaccuracy and unknowns on both sides of the 'scale'. I explained this a little yesterday, but there were two points that I didn't stress enough, and I have some of you to thank for raising them.

Energy sources

First, let's look hypothetically at someone whose energy intake is 3000 kCal per day, and who exercises regularly and is in weight balance. This person could, in theory, get that energy from 333 grams of fat. They could also get it from 750 g of starches. Neither is desirable, for both the obvious reason that a diet consiting entirely of only one food group would be sorely lacking in important nutrients and you'd end up less healthy than Morgan Spurlock (the guy from Supersize Me).

However, what is more vital is to recognize that you don't simply add up the numbers, because the macronutrients (carbs, fats and proteins) have a more complex role than simply adding calories to the body. Carbohydrates are the primary source of energy during exercise, and for the brain pretty much all the time. Fats play a role in cell function, and proteins are crucial for cell repair and for muscle recovery after exercise. You can have too little of each, particularly carbohydrates. Perhaps the biggest trend in fad diets in recent years is the shift away from carbohydrates, with the principle that fat can provide energy. That's true, but only up to a point, and an athlete without carbohydrates is a dangerous proposition - impaired performance and immune function are two of the consequences.

The point is that your objective with diet is not to simply tally up the calories, you also have to manage the diet for health reasons. There are many theories on how to achieve this - there's a 40-30-30 principle, which says that 40% of your energy should come from carbs, and 30% each from fats and proteins. Then there's the theory that those doing more exercise should aim for 60-30-10, then there are the "anti-carb" diets where only 10% of the energy comes from carbohydrates, with most from proteins. There is a great deal of debate around these diets, which balance is optimal. I'll try to get to that later in the series, or in a separate post in collaboration with a dietician (because if you want to offend people, tell them their diet is not optimal). I firmly believe, however, that anyone who is basing their weight loss on exercise, or who is training for performance, must ensure that their carbohydrate intake is sufficient, or they will be compromised.

Now, before this becomes a post of its own, let me address the second point.

Complexity in calories

Take the case of a person who has recently come down from 250 to 230 lbs, and is attempting to lose a further 20 lbs (± 10 kg), through the use of diet and exercise. But, much to their dismay, they lose nothing. Some will say that this person has matched their calories in and calories out but not lost weight, thus discrediting the principle.

The problem is, you can never know with certainty what has happened to energy output. Until you measure it exactly (which requires complex equipment and is highly impractical), you assume that calories out is accurate. It may not be - there is a lot of evidence that muscle becomes more efficient when weight is lost, which would impact on how the estimation for energy expenditure is made. Suddenly the energy intake is again greater than it should be.

Similarly, metabolic adaptations to conserve energy have been identified. For example, a reduction in body weight (specifically, fat) causes a fall in the levels of two hormones, leptin and thyroid hormone. Problem is, when these hormone levels fall, appetite rises and metabolic rate actually goes down. If you inject leptin, incidentally, you can prevent this drop in metabolic rate (Rosenbaum, 2002 & Rosenbaum, 2005). So, referring again to the figure from yesterday (shown again below, but with the modification after metabolic adjustments), your body actually reduces the resting energy expenditure in response to weight loss, which may create an energy surplus.

This is yet another reason why I don't advise the approach of counting calories to try to match the two sides - your body is too smart, and too complex for that in the longer term! Trying to pre-emptively calculate the body's response is fraught with error, because of inaccuracy of measurement, and complexity of physiology. Yesterday, I mentioned the example of an individual who remains weight stable over a 10 year period. What I was getting at, but didn't put across correctly, is that weight balance is incredibly complex - over 9 million calories balanced in a ten-year period. That doesn't happen by accident, and it doesn't happen by preemptive design. It happens by physiology! And so losing weight requires the same principle - don't micro-manage the scale, rather be sensible and allow the theory to work for you, not to work the theory!

Final word on appetite

Then finally, something I absolutely must cover (and hope to) is the "listen to your appetite" theory. Your body is remarkable and it does signal to us when we need to rest, to eat, to drink, and even what (a salt craving for example, is part of the exquisitely regulated osmolality homeostat that sports drink companies don't want to recognize!).

However, in the case of diet, we're subjected to too many external influences that affect appetite that many people cannot rely solely on how they feel in order to eat correctly. There's some great research on this - Brian Wansink has done some studies with interesting titles like "Is this a meal or snack? Situational cues that drive perceptions.", and "How visibility and convenience influence candy consumption." He has also written a book called Mindless Eating: Why We Eat More Than We Think, detailing this fascinating phenomenon. (just a note - at the end of the series, I'll do a book list with some recommended reading on weight loss, looking at both exercise and diet)

Then there is the psychological component of food, which cannot be ignored, because our desire to eat is not simply 'physiological' in that stress and emotional cues trigger eating (we all know this as "comfort food", among other things). I would argue that these are still physiological, mediated by neurotransmitters in the brain, but this is semantics. Point is, we may not be able to trust that our body signals when to stop or to cut back. And then finally, I've already mentioned that with reduced weight (and fat mass) comes a fall in leptin, which then increases our appetites, playing havoc with the theory as our weight changes.

All in all, a complex issue, and another one to tackle in detail later (if not in this series, then in another).

Looking ahead

So that's it for my "short" reply to your posts. I just wanted to consolidate yesterday's posts, but I guess there were a couple of key points to make. The principle of increasing energy expenditure and cutting down energy intake is without doubt the simple solution. Achieving this is difficult (but this does not make the principle wrong, take note), and there is a physiological layer of complexity that makes it impossible to preemptively manage energy in and energy out. What it boils down to is systematic sensible choice, with expert support to get the principles correct.

Part 3 on fat is on the way - probably later in the week, I have a presentation to work on first, so forgive the sudden "loss in momentum" of the series.

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Comments:

With regards to appetite and listening to your body as a means of gauging how much to eat, I think that we must consider why our feeling of appetite exists. I mean this in a historic/evolutionary sense. Humans evolved in a world where food was scarce. Finding adequate calories literally took most of the day. Only in human's very recent history has it become relatively easy to eat too much.

The point here is that from an evolutionary standpoint, we have developed this sense of hunger very keenly -- starvation was a real threat. The feeling of full wasn't a problem. That is to say there was never any natural selection against eating too much --because in large part, it never happened.

The net effect today is that we do not have a well developed sense of fullness. Sure, we're good at feeling hungry because all through history we were on the verge of starvation, but evolution is playing a long game of catch up when it comes to telling us to eat less. Thus, it seems to me that listening to our bodies, when it comes to our appetite, may not actually be the best way to go.

What I love about physiology is how complex it is. It is amazing that we regulate caloric intake as well as we do. I had a professor in exercise physiology made the point that if you ate just one potato chip a day too much that would be one pound a year, but 10 pounds a decade and before you know it you are 20-30 pounds overweight.

I believe that one of the greatest defect that most diets share is the speed that they are expected to work. Many dieters expect significant losses in a matter of weeks, and inevitably get into an oscillating weight situation due to rising and falling motivation.

My current weight loss goal is one pound per month! I weigh myself on the first five mornings of the month on a digital scale, and average. If I don't make my one pound goal, I'll make a tiny adjustment to my eating habits, skipping an evening snack, say, and wait another month to see the results.

This won't work for the person eager to lose 20 pounds in advance of a beach vacation six weeks hence, but I believe it could help people maintain their weight in the long run.

I'll again (as I said to part 2) say that I love this blog, but I will also still - but subtly - disagree with the premise that counting calories won't work.

Perhaps what Tom Henning in the third post said is the key - calorie counting isn't a quick thing.

Responding specifically to the main post, it's clear there is uncertainty how many calories your body even needs in order to be in balance, and obviously water plays a big role in day to day body weight

Without attempting to be a shill (since it's free, and not faddish) the Hackers Diet attempts to resolve both of these problems with what you could consider a multi-week "TARE" exercise - a slow study to find your true basal metabolism expressed in calories.

In other words, before you even attempt to run a deficit and lose weight, you spend a couple weeks just counting calories and weighing daily - but *not* attempting any changes to see what happens to your weight.

Over time you can take the daily weights (at the same time of day) from the days you counted but weren't changing diet, smooth them out with an exponentially backed off moving average and determine what your *current* basal metabolism is, expressed in calories, by taking your input, and adjusting it by whatever the gain or loss was to infer the real balance number.

Then you can work that basal rate minus a steady/safe deficiency (say, 500cal/day to lose a pound a week) into a well-balanced but calorie deficient diet and you should see weight loss.

After some serious weight changes it's almost a sure thing your body will start adapting to it, so you may need to reset the basal metabolism number with another extended "TARE" session then re-do another diet plan to stay deficient and well-balanced

As for measuring devices being impractical, compared to the cost major health issues, it actually isn't too expensive to get a power meter for a bicycle these days. Then you can measure everything down to kilojoules in consumer hardware, and use typical efficiencies to back the kilojoules into kilocalories.

Yes, there's uncertainty here - perhaps you have such huge water weight fluctuations that even 3 weeks of measurements still aren't statistically significant for determining basal metabolism in kcals. Perhaps your output efficiency doesn't match closely with averages so output is wildly skewed.

But I do contend that for most folks you can get pretty close to knowing the correct "in" numbers, and you can get the "out" numbers too. I haven't seen anything here yet that didn't seem rather hand-wavy in saying it wasn't - I only see it said that it's hard and thus not recommended. I contend that it actually isn't that hard, and should be recommended in more cases. Any athlete that can follow a training plan should be able to execute for instance - that's a much higher bar than "general populace", but it's a huge swatch compared to "only elite people".

I am a USA Cycling coach in Dallas, TX. This series of yours is off to a great start!

In my experience, getting enough grams of carbs to provide fuel for exercise isn't easy. Focusing on getting the carbs right requires you make really careful choices or you fall into the trap of pulling in unwanted, unneeded grams of fat & protein. I fully agree with you that many athletes are very likely under-carbed & this explains poor performance & possibly some health issues, as well.

I look forward to your analysis of the carbs issue & the rest of the series!

Thank you for the interesting posts. As someone who has lost weight over the last three years (50lbs) I am a proponent of calorie counting, as an estimate of what I consume during the small meals I have spread throughout the day. What I found to be of great help was the resting metabolic rate done by my coach, which provided me with a baseline starting point. This was followed by VO2 testing for two exercise disciplines. I have hit at least two plateaus during this time in which I had to step back and reanalyze what I was taking in. You are correct that counting calories is more of an estimate which puts you in tune with what you are eating. It has also influenced better decisions when eating out as after a point you can provide a pretty accurate estimate of calories in anything you may order.

I do have one question though. My coach tells me I should intake 30% of my calories in as protein to ensure muscle building and recovery during this part of the season in which most folks are focusing on strength. I do have protein as part of every meal but find that aiming for 30% per day is daunting, especially being a vegetarian. I have tried protein shakes in the morning, hemp, soy and whey and find that I feel pretty aweful until I go back to about 20% per day.

I've been reading your book, The Runner's Body and was interested to see that each person is different, if you are used to having more protein in your diet one is more able to handle it. So how can you be sure you are getting enough protein for proper muscle building and weight loss if all you feel is nauseous and off kilter? What I have done works so far, but I also wonder if accomplishing an increase in protein would provides some benefits strength wise for the long term.

It would be interesting to know your thoughts on protein intake when addressing the "calorie complexities."

Great set of articles, as usual!! A testimony on the general topic, use it if you want to.

My experience with excercise and diet span 15 months now. Since then I came down from 103kg to 85kg now. Have not had a fat% measurement in months but last one was less than 10%. I am a 43 year old serious "social but competitive'cyclist. I learned that you need to exercise and plan and stick to a diet. I train every day for at least 5 days / week but that had limited effect. Took me down to 98kg's only. Then used advise of a dietician called Andy Lambert who limited my calorie intake and divided the fat, carbs and protein intake and spread the meals to 7 daily from 3. (I never go hungry and I believe that makes the difference as it prevents cravings and over indulging). Obviously I stick to the eating plan and cut all fats and sugars not needed and excess protein.

It takes time!! You need to give it a year to reach your target weight less you are very fortunate.

Some athletes obviously train their bodies better than others to compete without food (carbs). I am still a big guy and need my food so I take food with the liquid carbs and gu on long rides and competitions. Doing yesterday's climbing race again my sandwich after the first 40 made a big difference as I could handle the hills to the end. So less you are experienced in competing with little food I recommend a small sandwich with a bit of protein.

I lost 50 pounds and have kept it off for 6 years. I like a lot of what has been said, and I used these principles myself. But it doesn't need to be hard. Here is a super-simple weight-loss system that requires no math and really works!!

* Keep a log of everything you eat for a week or two. This teaches you about your own diet. You don't ever need to keep a food log after this.* As creatures of habit, we tend to eat the same things week after week.* Slowly, change your habitual diet. Make small calorie-reducing substitutions in your habitual diet. The changes should be small enough that you hardly notice and you should not make too many changes at once.* Over time you will gradually lose weight.

What about exercise? Exercise as much as possible to stay healthy. But if you don't already do regular exercise then hold off until you start to see results from the program above. Otherwise, you will complicate things due to possible over-compensation.

The topic should be "weight management", not just loss. Some people think the issue is over when they hit target. A healthy relationship with food is critical to being a healthy weight even more than it is to reaching a healthy weight: people can suffer through all sorts of perverse regimens for a few months.

Speaking of puns, I always read about the "growing" problem of obesity with a chuckle.

I enjoyed Morgan Spurlock's "Supersize Me", which went way beyond an interesting (but unreal) experiment, and shed a lot of light on the changes in the American eating habits. (A few of my friends simply dismissed him because they focused on the 30 day experiment).

One important variable in the weight loss debate is what I consider to be the addictive nature of junk food. People get addicted to the excess salt, fat, sugar and refined carbohydrates in junk food. An addiction is hard to break so most people have a hard time changing their eating habits, their caloric intake remains excessively high, and they don’t loose weight in spite of all the exercise they do.

While growing up I was fortunate to eat almost exclusively home made meals that left me full and satisfied for a long time. As an adult though, I slowly became addicted to junk food and it seemed that I couldn't get enough and felt hungry shortly after. This made me snack on more junk before the next meal. It took me a while to gradually change my eating habits. I now follow an established eating routine of healthier foods and don’t have cravings for midmorning or midafternoon snacks anymore.

While your blog concentrate on athletes, when you jump into broader social issues, I think some of your science breaks down.

For Joe/Jane sixpack, I would argue many maintain a weight for many symbolic reasons just as when people some people try quitting cigarettes. There is all kinds of emotional/psychological stuff wrapped up in anyone's body image.

Therefore the act of losing measured weight is by itself only a very small part of the obesity problem.

Ross: Thanks for this great topic. Good luck dealing with everyone's pet weight-loss "theory." Here's the one I can't resolve: According to Cordain, the Paleo Diet was rather high protein. And yet Paleo guys and gals presumably had to scamper around a good bit every day to insure their survival. How did they do this on a low-carb diet? I'm guessing you might suggest that Paleo activity intensity was quite low. But I'll wait to find out. Best, Amby

I understand that metabolism will decrease when you are in a caloric deficient state, however, 1)how much and how long does it take to significantly change your basal metabolic rate (and how much does it change)? And 2)would exercise (known to stimulate metabolism) and a change in body composition (increase muscle mass and decrease fat mass) negate this potential decrease in resting metabolic rate? If so, this is one reason why nutrition + exercise may be the most effective way to lose weight! Forgive me as I am naive to this area of research. Thanks for your help.

This is my first time on your blog and while I rarely comment, I felt compelled because it is so fantastic! As a graduate student with similar interests I am glad to have found such great writing. I feel as though I could spend hours here reading...and not working on the paper I have due next week...

I would appreciate it if you could comment on the idea of a "set point," that your body tries to maintain the same weight all the time, regardless of how hard to exercise and how much you eat. My wife struggles with her weight, but has found that it seems to average out to the same number over the course of several years. I guess your mention of a reduction in resting energy expenditure could facilitate this effect, but I was wondering if you could comment on it specifically. Thanks.

That's really interesting, thank you! I do agree with pretty much all of it. We're heading in that direction, by the way.

The plan is to do the next two articles on fat and carbohydrates during exercise (basic physiology, when does your body burn which fuel), and then I was going to talk a little about the types of training and make some practical recommendations.

The series looks really interesting. Just a couple of points about calorie counting: obviously this is not an exact science, and it's all too easy to be out a few hundred kcal on either side of the equation. Lifestyle changes (rules such as consuming more protein and vegetables) I think are mostly likely to people with a fair amount of weight to lose, because the less energy dense foods become more prominent in the diet and weight can drop fairly quickly, especially if some activity is added in. Once people have established such habits and are trying to lose that last 20 pounds, though, it's pretty difficult to do without some kind of counting/measuring.

Even for people who don't plan to count, I think it's a great idea to get a small scale and weigh out the portions of what you're already eating. How much cereal are you really putting into your bowl? How much pasta into that pot? Is that apple really 60kcal or is one of those monster apples that is twice the size? How about that bagel? Getting some sense of the energy content of your most frequently eaten foods can really help you recalibrate.

Another factor is body size. Someone who weighs 200 pounds has a lot more wiggle room than, say, a 5 foot woman with a desk job who is trying to lose twenty pounds.

I would just like to point out two points, 1. that not all calories are created and/or are processed equally by the body and 2. Many athletes do quite well on ketogenic diets.

Point 1. the Kcal derived from a carbohydrate pretty much supplies your body with 1 Kcal's worth of energy because it is easily absorbed into the blood stream. 1 Kcal of fat on the other hand must go through a series of chemical processes to be turned into a sugar before it can be used to fuel the body. In each of these chemical processes, some energy is lost (2nd law of thermodynamics) so by the time you are using that fat for energy, 30-40% of it has already been lost in the process of converting it. This is one reason why low carb diets work, the body has to work harder to change protein and fat macronutrients into usable food energy. You could eat 2000Kcal a day of exclusively protein and fat and have the same net effect as eating 1200 Kcal a day of carbohydrate.Point 2. The human body is actually very well adapted to performing on low carb or ketogenic diets. Early humans did not have access to carbohydrate dense foods. the vast majority of their food supply was meat based, protein and fat. They were able to function just fine as persistence hunters however because the human body's liver is designed to turn fat into glucose. Until recently, cultures such as the Inuit survived and performed great feats of endurance on a diet that consisted of about 75% whale blubber. For us modern humans it takes a few weeks to get your body used to it but once it does most are able to perform quite well without much in the way of carbs.

I would like to echo Mike Hardy's comments, regarding calorie counting and the Hacker's Diet, but I will be more blunt.

I believe the argument that "calorie counting is not a good way to lose weight -- it's too complicated" does enormous damage. Why? Because it discourages people from even trying to lose weight. Ten years ago, I read the Hacker's Diet. It made sense to me. I understood it, and believed that if I followed it, it would work. Over the next year I lost 50 pounds, counting calories and plotting my weight trend, and I've kept it off since then. Last year I ran 20 marathons, including a sub-3 at Boston.

If I had read this blog instead of the Hacker's Diet, I would quite likely still weigh 215 pounds, or maybe more. I would have just been too discouraged, convinced that body weight is unmanageable by rational, controllable means.

Let's look more specifically at the problems you and some commenters have raised with calorie counting.

First, that it requires too much accuracy. You point out that if you're off by 19 calories / day, you can gain 10kg over 10 years. And nobody can count calories in vs. out to that level of precision. Well yes -- but don't you think you'll notice something is off, long before you've gained 10kg? How is it that I've been able to maintain my weight for ten years by counting calories?

For counting calories (at least, the Hacker's Diet way) to work, you don't have to know exactly how much you eat and how much you burn. Why? Because you get feedback, by observing what your weight -- or, better, what your smoothed weight trend -- actually does. You make an estimate of what you burn, and you count what you eat as well as you can. Yes, there's noise, but any systematic error will manifest itself in what it does to your weight trend, and then you just correct, by adjusting your estimate of what you burn. (It doesn't matter if your systematic error is really in counting what you eat -- the result will be the same.)

Yes, it really is that simple. In practice, the lack of accuracy in counting is not a problem at all, given very simple tools and practices. That is an empirical fact. It is a tragedy that this fact is not widely appreciated.

Second, you describe various sources of complexity in calories -- metabolic changes in how calories are burned, as a function of changing body composition, hormonal levels, etc. But this too is easily handled by the simple feedback mechanism of adjusting your estimate of what you burn, based on the ground truth of what the scale says. For example, If you expect, based on your counts, to be losing a pound / week, and over several weeks your trend line averages a slope of only -1/2 pound / week, then you know you need to drop your estimate of what you burn by about 250 cal. / day.

You write "As I stressed yesterday, weight loss is not simple (obesity wouldn't be the fastest growing cause of death if it were)".

But it IS simple! The problem is not that it isn't simple; it's that we are not told the simple way to do it. We're told either to follow simple diets that clearly, energetically, don't work, or that it is very complicated. Both are wrong.

Your personal testimony is wonderful, and congratulations. But don't forget the legions of people who have failed trying to do what you advocate as the method to lose weight. I guarantee you that for every one of you who has succeeded on this Hackers diet, there are ten who have failed. Yet your personal experience makes the post and all the commenters wrong?

You and Mike may be the exception, but your example doesn't make the principle wrong. And the post doesn't say you're wrong, just that it's not recommended. What you don't realize is that your experience leads others into a doomed practice. That's the tragedy.

Glad you lost weight. Now, if I only had a dollar for every guy who reckons it's simple...

Not "Anonymous" here, but Ross (we sign our comments as "Ross Tucker and Jonathan Dugas", by the way - you can see some of them higher up.

We've often encouraged people to put names on their posts, but it's OK if they don't. I mean, if the post you're questioning said "Paul" at the bottom, would it change the response? So I don't mind the anonymous posting, though it is of course nice to address people by name.

To anonymous, what part of the posts did I not read correctly? The one quote that I think it is fair to say summarizes the issue is this: "Now, the point is that you cannot measure these things accurately, and therefore you cannot micro-manage this." This is what I am disputing.

You're right of course that personal anecdotes from Mike and myself don't prove that everyone will have the same experience on the Hacker's Diet, but I would be quite surprised if 9/10 who seriously try it fail. The biggest reason people fail counting calories, I think, is actually one that I haven't seen mentioned here: water noise. Not only can you not accurately measure what you eat and what you burn; you can't even accurately measure what you weigh, because of daily water fluctuations on the order of a couple of pounds. This noisy signal is what makes getting accurate feedback difficult, and getting accurate feedback is the one thing that is essential, because it's how you manage to make it work in spite of measurement inaccuracies. And it's one thing the Hacker's Diet fixes, by forcing you to observe your daily weight trend, an appropriately smoothed moving average which filters out the water noise.

Also, I never said that losing weight with the Hacker's Diet was easy, merely that it is simple. It still takes hard work. My point here was to show that in spite of all the very reasonable-sounding logic that says that counting calories is doomed to fail, in practice, with a few simple bookkeeping tricks, it can work quite well. And I stand by my assertion that it's a tragedy this is not more widely understood.

Ross: Thanks for this great topic. Good luck dealing with everyone's pet weight-loss "theory." Here's the one I can't resolve: According to Cordain, the Paleo Diet was rather high protein. And yet Paleo guys and gals presumably had to scamper around a good bit every day to insure their survival. How did they do this on a low-carb diet? I'm guessing you might suggest that Paleo activity intensity was quite low. But I'll wait to find out. Best, Amby

Jonathan Dugas, PhDCurrent residence:Chicago, USAEmployment: Director of Clinical Development, The Vitality GroupResearch interests: Temperature regulation and exercise performance, with a special emphasis on how fluid ingestion affects those two things. In addition, the effects of exercise on health improvement and risk modification in large populationsSports interests: Cycling, running, triathlon, endurance sports

Full discolusre:The views expressed on this site are not those of the University of Cape Town (UCT), the Sports Science Institute of SA (SSISA), The Vitality Group, or Discovery Holdings.